The NIH Working Group on Diversity in the Biomedical Research Workforce recently released a set of recommendations to improve the diversity of the research workforce, including establishing a system of mentorship networks for underrepresented minority students that will provide career guidance throughout their career development. To that end, this R25 application responds to PAR-10-173 (NIDA Research Education Program for Clinical Researchers and Clinicians) and seeks five years of funding for the UCLA HIV/AIDS, Substance Abuse, and Trauma Training Program (hereafter, Program). The Program mission is to provide training and mentorship to early career clinician researchers or post-doctoral scholars who are ethnically and culturally diverse and whose focus is reducing substance abuse and HIV transmission in underserved populations at high risk for traumatic stress and health disparities. The goal is for Scholars to establish career independence, including NIH funding for their research. This program represents an evolution of our multidisciplinary, multiethnic team's NIMH ARRA-funded HIV/AIDS Translational Training Program, which successfully provided two years of training and mentorship to five postdoctoral scholars, several of whom have received or are seeking NIDA funding. Our pilot program highlighted the need to make substance abuse and traumatic stress more central to the Program's conceptual orientation because this link has not been the focus of training grants that target underserved populations at risk for HIV and health disparities. Our Program will provide a two-year course of training and mentorship to a total of 20 (five per year for 4 years) early career clinical researchers and post-doctoral scholars who hold funded fellowships or other academic positions but need specific training in HIV/AIDS, substance abuse, traumatic stress and health disparities. Underserved populations, particularly those racial/ethnic minority populations, are disproportionately affected by substance abuse and HIV/AIDS and typically experience a high degree of traumatic stress. To learn about the confluence of these phenomena, Scholars will attend two week-long Institutes per year for two years and will receive continual, personalized career mentoring, training, and research supervision. Each cohort of Scholars will be followed for the duration of the training grant and each cohort will present their research in Year 2, form a network of collaborative mentoring, and come together in Year 5 to share their experiences and progress in achieving Program goals. Scholars will be mentored by a core faculty mentor as well as a home mentor, i.e., someone regularly accessible to the Scholar who has the relevant expertise and commitment to mentoring the Scholar for the duration of the Program. Each Scholar will be expected to use pilot funding from the Program to conduct research (e.g., qualitative study, secondary analyses, etc.) that will serve as preliminary studies in their NIDA application during their two year tenure.